1. Field of the Invention
The present invention relates to an image display system, an image transmission apparatus, an image transmission method, an image display apparatus, an image display method, and a program which are suitable to be applied to, for example, a monitoring system. In particular, this invention relates to an image display system and the like in which on an image transmission apparatus side, through carrying out a processing on respective image data from a plurality of camera sections generated adapted to pick up a panorama image, first compressed image data obtained by compression-encoding image data at a high resolution and second compressed image data obtained by compression-encoding image data at a low resolution are generated and transmitted, and on an image display apparatus side, the panorama image is displayed by using decoded data of plural pieces of the received second compressed image data, and the high resolution image is displayed by using, among the plural pieces of the received first compressed image data, decoded data of the first compressed image data of the divided images corresponding to the predetermined position determined on the panorama image, so that the data processing amount during the data transmission and image display is reduced and a processing load is alleviated.
2. Description of the Related Art
In recent years, the number of pixels provided in a digital camera and a video camera has been increased. A digital camera having more than 10 million pixels is commonly available, and a consumer-use HD (High Definition) video camera is also on the market. When image data obtained by capturing images with these cameras is transferred, an encoding processing is carried out in order to reduce a transfer band. Examples of the encoding processing mainly include JPEG, MPEG-2, and MPEG-4.
Attempts by using these encoding technologies for distributing high pixel images to a network such as the Internet are often practiced. For example, Japanese Unexamined Patent Application Publication Nos. 2003-18583 and 2005-333552 describe recording and distribution of a wide angle image (wide area image) by using a plurality of cameras. However, the distribution described in Japanese Unexamined Patent Application Publication No. 2003-18583 or 2005-333552 is of a type in which the image data is accumulated in a video server. As it is expected that the number of the pixels will be further increased in future, this type has a limitation in terms of scalability.
In a trend towards the higher number of pixels, for example, as described in Japanese unexamined Patent Application Publication Nos. 2003-162018 and 2002-314867, there is proposed an apparatus using a plurality of cameras in a viewpoint coincident optical system, and therefore the importance of the encoding processing in the image transfer is increased. As countermeasures for limiting the transfer band, a multi-resolution encoding or a rate control method in accordance with the band of a transfer path or on a reception side are conceivable. These methods are embodied with a technology of JPEG 2000 which is based on wavelet transformation.
Also, such a method is conceived that the data transfer among is reduce while in accordance with a change in situation, only a part determined to be necessary is transferred, and the data resolution is changed (for example, refer to Japanese Unexamined Patent Application Publication No. 2005-176301). However, according to the method disclosed in Japanese Unexamined Patent Application Publication No. 2005-176301, as an area determined to be unnecessary is previously sent out and the image of the necessary area is overlapped afterwards, a time difference between the peripheral area and the attention area may be generated. The method is effective in a situation where a change around the peripheral area is considered to be not large, but the method is not suitable in a case of sport broadcasting or concert broadcasting where images including peripheral areas need to be displayed in real time.
In addition, an embodiment using a wide angle image pickup system such as a fish-eye lens is also proposed. However, in many cases, a subject at far becomes smaller, and a distance at which monitoring can be performed on entering people is a disadvantage compared with a normal zoom type monitoring camera.
Furthermore, as a camera for capturing images at a plurality of resolutions in real time, for example, there is conceived, as disclosed in Japanese Unexamined Patent Application Publication No. 7-143439, a camera in which a low resolution motion picture is associated with a high resolution motion picture, or as disclosed in Japanese Unexamined Patent Application Publication No. 2005-197948, a camera in which a low resolution image is generated based on a high resolution image and the images are formed into a motion picture. However, both of the apparatuses are not an apparatus for displaying a high resolution motion picture.
Moreover, Japanese Unexamined Patent Application Publication No. 2004-62103 discloses a method of dividing and displaying images on a single HD (High Definition) image based on a coordinate conversion table in which signals from a plurality of cameras are previously obtained. An advantage of this method resides in that a target image can be obtained in real time when a panorama image is generated from the plurality of divided images by using the coordinate conversion table.